The generally recognized F figure wrench, as depicted in U.S. Pat. No. 6,220,125 FIG. 3, has an angle adjusting device functioning so a cam 8 implemented on a rod body 9 pushes an arresting member 10 to retain a driving head 11, thereby position of the driving head that has been adjusted can be locked in; to release the locked-in driving head position, the rod body will need to be turned and then the arresting member will no longer retain the driving head, then the angle of the driving head will be free to be adjusted; to lock the driving head in position again, the rod body will need to be turned to have the cam push the arresting member to retain the driving head in desired position. Nevertheless, the angle adjusting device of the generally recognized F figure wrench is in an unstable situation when its arresting member 10 is not in contact with its rod body, which will create fault function and damage to the parts of the wrench, therefore improvement on the angle adjusting device is presumed required.